In recent years, as a display device substituted for a liquid crystal display device, an organic electroluminescence display device (hereinafter, also simply abbreviated as an “organic EL display device”) using an organic electroluminescence element (hereinafter, also simply abbreviated as an “organic EL element”) has attracted attention. The organic EL display device is a self-luminous type, has a characteristic of low power consumption, and is considered to have sufficient responsiveness even to a high-definition high-speed video signal. Development and commercialization of the organic EL display device for practical use are keenly proceeding.
In the organic EL display device, high contrast and high color reproducibility can be realized, for example, by constituting one pixel with three sub-pixels (light emitting elements) constituted by a sub-pixel having a red light emitting layer and constituted by a light emitting element that emits red light, a sub-pixel having a green light emitting layer and constituted by a light emitting element that emits green light, and a sub-pixel having a blue light emitting layer and constituted by a light emitting element that emits blue light. Meanwhile, reduction of a pixel pitch is required for high resolution. However, it becomes more difficult to constitute one pixel with such three sub-pixels as the pixel pitch becomes finer.
Therefore, development of a method for forming a white light emitting layer over all pixels and coloring white light using a color filter, that is, development of technology for constituting one pixel with three kinds of sub-pixels (light emitting elements) of a red sub-pixel (referred to as a “red light emitting element”) obtained by combining a light emitting element having a white light emitting layer (referred to as a “white light emitting element”) and a red color filter, a green sub-pixel (referred to as a “green light emitting element”) obtained by combining a white light emitting element and a green color filter, and a blue sub-pixel (referred to as a “blue light emitting element”) obtained by combining a white light emitting element and a blue color filter is proceeding. The white light emitting layer is formed as a continuous layer over the entire white light emitting element. It is unnecessary to form the red light emitting layer, the green light emitting layer, and the blue light emitting layer for each sub-pixel. Therefore, the pixel pitch can be fine. In each of the white light emitting elements, the white light emitting layer is formed between a first electrode and a second electrode. The first electrode is formed independently in each of the light emitting elements. Meanwhile, the second electrode is common in each of the light emitting elements.
As technology for improving a light extraction efficiency in a pixel having such a configuration, there is technology for amplifying light emitted from each of light emitting elements by optimizing a cavity structure in each of the red light emitting element, the green light emitting element, and the blue light emitting element. Specifically, for example, as disclosed in Japanese Patent Application Laid-Open No. 2009-091223, a light reflecting layer is formed below a first electrode including a transparent electrode, and a second electrode including a semi-light transmitting material and the light reflecting layer constitute a resonator structure. In addition, light emitted from a light emitting layer is resonated between the light reflecting layer and the second electrode, and a part of the light is emitted from the second electrode.